EP0195595A2
Expired / Lapsed
EP
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Local area network
Assignee: NCR International Inc
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Filing: 1986-03-13
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Granted: —
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Expires: 2006-03-13
Abstract
Abstract A modular, hierarchical local area network is realizable by using existing twisted pair wiring, for example, in a building together with several elements known as network access units and hub units. A network access unit is connected to a device (microprocessor, display terminal, peripheral device, other local area network, information systems network or the like) in the local area network to give that device access to and from the network. The network access device is designed for simple daisy chaining with other devices to form a node 210-1, 210-K when devices are colocated in the same section or room in the building. The hub unit 230 is the network building block which permits extensive expansion of the local area network. It provides a connection point for access units or other hub units, performs collision detection operations, if necessary, and serves as a loopback point for the network. Switchably connectable termination impedances and loop-backs are automatically passed to the appropriate points in the local area network. While most small local area networks are considered for intra-building applications, the present network is applicable to inter-building applications, also.
Inventors
- 👤 William Louis Aranguren
- 👤 Mario Alberto Restrepo
- 👤 Michael John Sidey
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 16:31
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/44
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
282 words
A local area network arrangement for providing communications on first and second segmented transmission means (120-1; 120-N) among a plurality of devices, each device communicating through a network access means 1 20 connected to the device and to the first and second segmented transmission means, each network access means CHARACTERIZED BY transceiver means 140, 141 for translating signals from the device to the first segmented transmission means and for translating signals from the second segmented transmission means to the device, a first port including input terminal means (121-1,122-1) for connecting the first segmented transmission means thereto, output terminal means 123, 124 for connecting the second segmented transmission means thereto, and first and second characteristic termination impedance means 150, 170; 1 51, 1 71 switchably connected separately in circuit to the input and output terminal means, respectively, only in the absence of connection between the segmented transmission means and the first port, and a second port including input terminal means 1 1 7, 1 1 8 for connecting the second segmented transmission means thereto, output terminal means 115, 116 for connecting the first segmented transmission means thereto, and loop back means 150,153 switchably connected from the input terminal means to the output terminal means of the second port for providing a low impedance electrical path therebetween only in the absence of a connection between the segmented transmission means and the second port, the input and output terminal means of the first port being connected directly to the output and input terminal means, respectively, of the second port, the second port of each network access means adapted for connection via the segmented transmission means to the first port of an adjacent network access means.
Claim 2
Dependent Claim
282 words
A local area network arrangement for providing communications on first and second segmented transmission means (120-1; 120-N) among a plurality of devices, each device communicating through a network access means 1 20 connected to the device and to the first and second segmented transmission means, each network access means CHARACTERIZED BY transceiver means 140, 141 for translating signals from the device to the first segmented transmission means and for translating signals from the second segmented transmission means to the device, a first port including input terminal means (121-1,122-1) for connecting the first segmented transmission means thereto, output terminal means 123, 124 for connecting the second segmented transmission means thereto, and first and second characteristic termination impedance means 150, 170; 1 51, 1 71 switchably connected separately in circuit to the input and output terminal means, respectively, only in the absence of connection between the segmented transmission means and the first port, and a second port including input terminal means 1 1 7, 1 1 8 for connecting the second segmented transmission means thereto, output terminal means 115, 116 for connecting the first segmented transmission means thereto, and loop back means 150,153 switchably connected from the input terminal means to the output terminal means of the second port for providing a low impedance electrical path therebetween only in the absence of a connection between the segmented transmission means and the second port, the input and output terminal means of the first port being connected directly to the output and input terminal means, respectively, of the second port, the second port of each network access means adapted for connection via the segmented transmission means to the first port of an adjacent network access means.
Claim 3
Dependent Claim
286 words
The local area network arrangement as defined in claim 1 characterized in that the local area network is further comprised of at least first hub means (Fig. 5), 250 (Fig.2) for expanding the area network by providing interconnec- tivity between other such hub means and network access means via first and second segmented transmission means, the at least first hub means including, first and second common bus means 507, 508, first through K-th ports, each port having both input terminal means 501, 502 for connecting the first segmented transmission means thereto and output terminal means 502, 504 for connecting the second segmented transmission means thereto, first through K-th port circuit means, each port circuit means 500 being connected to the corresponding port for translating signals from the input terminal means to the first common bus means and for translating signals from the second common bus means to the output terminal means, an access means 511 connected in circuit relationship to the first and second common bus means for translating signals from the first common bus means to the first segmented transmission means and for translating signals from the second segmented transmission means to the second common bus means, and a (K + 1 )th port including input terminal means 251-3, 251-4 for connecting the second segmented transmission means thereto, output terminal means 251-1, 251-2 for connecting the first segmented transmission means thereto, and loop back means 150, 153 (Fig. 4) switchably connected from the input terminal means to the output terminal means of the (K + 1 )th port for providing a low impedance electrical path therebetween only in the absence of a connection between the segmented transmission means and the (K + 1 )th port.
Claim 4
Dependent Claim
90 words
The local area network arrangement as defined in claim 2 characterized in that the at least first hub means further includes collision detection means 510 connected to the first common bus means and the access means for determining the occurrence of a collision between two or more signals on the first common bus means and supplying a collision signal representing such collision occurrence to the access means and, in the absence of signal collision, for permitting transmission of the signal on the first common bus means to the access means.
Claim 5
Dependent Claim
32 words
The local area network arrangement as defined in claim 3 characterized in that the collision detection means is connected in the circuit between the first common bus means and the access means.
Claim 6
Dependent Claim
37 words
The local area network arrangement as defined in claim 4 characterized in that the collision detection means, upon detection of signal collision on the first common bus means, inhibits transmission of colliding signals to the access means.
Claim 7
Dependent Claim
49 words
The local area network arrangement as defined in any of claims 2 to 5 characterized in that the first common bus means is a K-input logic element 6 1 0 (Fig. 6) capable of performing a logical OR function on the signals from first through K-th port circuit means.
Claim 8
Dependent Claim
38 words
The local area network arrangement as defined in any of the preceding claims characterized in that the first segmented transmission means is a twisted pair of wires and the segmented transmission means is a twisted pair of wires.
References Cited (Backward Citations)
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